Project-I:Controlling of magnetic states in Ferromagnetic Nanorings
(Application for Data Storage and MRAM devices)

Ferromagnetic nanorings have potential
applications to high density data storage and MRAM (Magneto resistive random
access memory) devices due to their potential to store information with
magnetic properties instead of electric. Ferromagnetic rings have been
proposed as a practical type of non-volatile data storage devices. Three
novel states exhibit by nanorings are single
domain, onion, and vortex. In addition to these twisted state has been observed.
Rotational or translational motion of the DWs observed during the switching
from onion to reverse onion or onion to vortex state.

We came upon a method of manipulating the magnetic states of individual
ferromagnetic nanorings using an azimuthalOersted field
directed along the ring arm circumference. The direction and magnitude of the
field are determined by passing a current through a solid metal atomic force
microscope probe into a metal under layer. Nanorings are fabricated by electron-beam lithography
techniques with electron beam evaporation of magnetic materials followed by
lift-up method.

(a)Schematic of the experiment setup. (b) A current-voltage plot
generated directly from the experimental setup in (a).

By applying circular field we can directly switch from
Onion to Vortex-CWand Vortex-CCW states. We can also switch between two vortex
state with applied CW and CCW circular field.

Onion-Vortex-Onion switching
process in symmetric CoNR

Onion-Vortex-Onion switching
process in asymmetric CoNR

Novel magnetic states observed in ferromagnetic nanorings

Project-II:Study of Domain Wall motion in ferromagnetic nanowires
by injecting current pulses